Improve chalk integration

[matthewjasper]

• Support subtype bounds in chalk lowering
• Handle universes in canonicalization
• Handle type parameters in chalk responses
• Use chalk_ir::LifetimeData::Empty for ty::ReEmpty
• Remove ignore-compare-mode-chalk for tests that no longer hang (they may still fail or ICE)

This is enough to get a hello world program to compile with -Zchalk now. Some of the remaining issues that are needed to get Chalk integration working on larger programs are:

• Ambiguity problems with associated types chalk#234
• Support const evaluation chalk#548
• Auto traits are not handled for generic closures  chalk#734
• Generators are handled differently in chalk and rustc

r? @jackh726